U.S. Pat. No. 4,157,462, Sensor, Houston F. Blanchard, issued June 5, 1979 and assigned to the assignee of this invention, discloses a roller band sensor which includes a pair of bands of flexible spring material of a generally figure-eight configuration which are constrained from their free shape to an elongate shape by the tapered side walls of a covered housing cavity. The adjacent abutting portions of the bands are commonly secured to each other and the respective remote portions of the bands are secured to a respective side wall of the housing. The integral biasing force of the bands tending to return to their free shape provides a preload force urging the bands toward the proximal end wall of the cavity to a preload position. When the bands are subjected to a predetermined velocity or acceleration change, the bands concurrently roll relative to each other and to a respective side wall of the cavity toward the distal end wall to actuated position wherein the bands engage contact means to actuate a device.
The factors which determine the movement of the bands to actuated position are: the natural frequency or spring rate of the bands, i.e. the predisposition of the bands to move when subjected to predetermined velocity or acceleration change; the preload; and the distance between preload and actuated positions. The desired preload and natural frequency are obtained by selection of the included angle between the side walls of the cavity and selection of the thickness of the bands. Air damping can be controlled through selection of clearances between the cavity covers and the band edges; notching or otherwise altering the profiles of the bands to provide air passages between the bands and covers; profiling the covers; or profiling the proximal end wall of the cavity.
U.S. Pat. No. 4,203,015, Roller Band Sensor Contact System, Lawrence D. Tuchscherer, issued May 13, 1980, and assigned to the assignee of this invention, discloses a roller band sensor having a contact system to eliminate contact bounce. Additionally, the Blanchard and Tuchscherer patents disclose various manners of avoiding interplay or substantial contact between the rearward arcuate walls of the cavity and the rearward loops of the roller bands to obviate such contact influencing the spring rate.